I. Field of the Invention
The present invention relates to an improved method and the related system for pneumatically transporting a powder or granular material in high density, and more particularly to a method of pneumatically transporting a powder or granular material contained in an airtight storage container efficiently to a collector at very slow speed while forming the material into a long column inside a transport pipe and to a system for practising the method.
II. Prior Art
FIG. 4 shows a powder or granular pneumatic transport system of a general type conventionally used. The system is of the construction in which the powder or granular material placed in an airtight storage container 100 is transferred from the container to a lower pipe 102a of a transport pipe 102 by the gas supplied from a gas feed pipe 101, and the material is formed into a plug-shaped material by supplying pressurized gas from a pressure nozzle 103 disposed intermediately of the lower pipe 102a, the plug-shaped material is pneumatically transported through an inclined pipe 102b of the transport pipe 102 through an upper pipe 102c and is finally received by a collector 104.
However, when the powder or granular material is pneumatically transported in the form of a plug by the system described above, clearance 106 is often formed above the plug-shaped material while it passes through the transport pipe 102 (see FIG. 5), with the result that the material A on the surface of the plug-shaped material 105 is first transferred and the plug shape is broken. Thus that eventually results in unsatisfactory transfer.
Moreover, since any of those conventional systems as described above transfers the plug-shaped material at an extremely fast speed like several meters per second for example, the material is obliged to incur strong shock when being received by the collector 104, thus easily incurring severe damage or disintegration.
Furthermore, that causes another problem of mutual collision between the powder or granular materials inside the transport pipe 102.
Accordingly, when the method above mentioned is applied to transporting of medicine tablets which are comparatively liable to break, a production rate of defectives tends to increase.